Residential Network Oversubscription

People sometimes notice, and complain, that they can’t get the bandwidth they’re contracted for consistently.  We certainly do.

However, in all fairness to the providers, most residential connections aren’t used very heavily at all.  To offer competitive prices, the upstream connections need to be oversubscribed (at least with DSL, we really can get our full contracted bandwidth as far as the first router at Qwest, because that last mile of copper is not shared).

Our household has four adults who use the internet fairly heavily, including for Netflix streaming and such.  One of us works from home across the internet.

And here’s what our last week of usage looks like:

This is based on sampling of counters in the router via SNMP every five minutes; our actual peaks certainly go higher than that (the connection has an inbound rated speed of 7 megabits).  Also note that the chart is in bytes; that top line represents 3.52 megabits per second, a full half of the rated speed.

(And to those few of you who may be thinking this looks rather a lot like an MRTG chart, yes, it does, doesn’t it?)